Safety device for presses.



R. B. BENJAMIN.

SAFETY DEVICE FOR PRESSES.

APPLICATION FILED APR- 25, I913.

L167A?5 Patented Jan. 11 1916.

2 SHEETS-SHEET 1.

R B. BENJAMIN.

SAFETY DEVICE FOR PRESSES.

APPLECATION FILED APR. 25, 1913.

LEGYAF Patented Jan. 11, 1916.

2 SHEETS-SHEET 2.

J2 J i H 1' l 0 I o: v1 i man ens nrnnr @JFFIC.

REUBEN B. BENJAMIN, OF CHICAGO, ILLINOIS, ASSIGINOB T BENJAMIN ELECTRIC MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SAFETY DEVICE FOR PRESS ESI Specification of Letters Patent.

- PatentedJan.1l1l,I9Il6.

Application filed April 25, 1913. Serial No. 763,578.

To all whom it may concern:

Be it known that I, REUBEN B. BENJAMIN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Safety Devices for Presses,

of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to improvements in safety manipulating devices for intermit= tently operated machinery, and particularly for intermittently operated punch presses and the like.

It is-one of the objects of my invention to provide means whereby the operators hands will always be in a position of safety before the press is caused to operate, thereby preventing the operator from getting his fingers or hands in the .machinery and maimed thereby.

To this end I provide a motor mechanism for operating the tripping mechanism, which motor mechanism is arranged to be set in operation by a pair of arms or handles,

which while being'connected to and movable with the hands of the operator do not interfere in any way with the movement of the hands of the operator, nor interfere with his properly manipulating the material to be worked upon. These two handles which are connected to the hands of the operator must be out of the danger zone of the press to insure absolute safety to the hands of the operator, before the tripping mechanism can be' caused to operate.

For the purpose of disclosing the present embodiment of my invention, I have illustrated one application thereof in the .ac-

. companying drawings, in which Figure 1 is .a side elevation of a punch press having one embodiment of my invention applied thereto; Fig. 2 is a front elevation thereof; and Fig. 3 is a diagrammatic view of the piping connection for the fluid under pressure to operate the motor.

In the drawings I have illustrated a punch press 1 which is of the usual construction and is provided with a suitable movable member 2 for trippingthe clutch to cause the press to operate. This movable member is operated by a fluid pressure motor 3, preferably in the form of a cylinder having a suitable piston 4 operating therein. This piston is connected by a latch,5, which is adapted to engage over a pin 6 on the rod 7, with the movable member of the tripping mechanism -2. The latch is normally held into engagementwith the pin 6 by means of a spring 7*, and is provided with a laterally extendlng arm 8 adapted, when the piston of the fluid pressuremotor is moved downwardly, to engage a pin 9 and thereby be disconnected from the movable member. The piston 4 of the motor is retracted to normal position by a coiled spring 10.

Fluid under pressure is admitted to the top of the cylinder of the fluid pressure motor by a pipe 11, which extends upwardly and passes across the top of the frame of the press to a suitable supply pipe 12. Interposed in the pipe 11 is a pair of threeway valves 13 and 14, these valves each having a suitable continuous opening 15 and a branch opening 16 in the movable member thereof which connects the pipe 12 with the pipe 11. The branch opening 16 when th valves are thrown in one position connects the pipe 11 with a suitable escape opening 17in the valve. These two valves for the purpose of admitting fluid under pressure to the motor 3 are arranged in series, while, as will be noted in the drawings, for the purpose of permitting the escape of the fluid under pressure in the motor they are arranged in multiple. That is, in order that fluid under pressure may be admitted to the motor both valves must be thrown to the admission position, while in order to permit the fluid under pressure to escape from the motor either of the valves may be thrown to an open position. i

The valve 14 is operated and controlled by a suitable arm 18, which is provided with a suitable connection with the valve so that the arm.may be swung into any position. However, this connection is such that in event the arm is swung forward or back ward the valve will be operated. The lower end of this arm is provided with a connection 19 by which the arm may be connected with one hand of the operator. The valve 13 is provided with a suitable arm 20 similar in construction and connection to the arm 18, and this arm 20 is likewise provided at its lower end with a connection 21 by which it may be connected to the other hand of the operator and caused to be moved therewith. The valves 13 and 14 are so constructed and arranged that when either hand of the operator, after being connected with the arms 20 and 18, is movedtoward the-operating mechanism of the press, the movable member of the valve which is connected to the moving hand will be rotated so as to bring the passage 16 in alinement with the pipe 11 and the rear end of the passage 15 in aliner'nnt with the escape port 17 The valves are also so arranged that when the hands of the operator are moved out of the danger zone of the press the passages 15 through each valve will connect the pipe 12 with the pipe 11, thereby permitting the admission of fluid under pressure to the cylinder of the fluid pressure motor.

In operation, we will assume that the parts are inthe position illustrated in the drawings. The operator having placed the material in the punch to be operated upon, moves both hands rearwardly until they are out of the zone of danger and the passageways 15 of the two valves connect the pipes 12 and 11. Fluid under pressure is thereby admitted to the top of the cylinder of the fluid pressure motor, causing the piston thereof to be forced downward and'carrying with it the operating rod 7 thereby moving the movable member 2 to trip the press. As soon as the piston has reached the downward limit of its movement the arm 8 of the catch 5 engages the pin 9, thereby throwing the catch 5 out of engagement with the pin 6 on the rod 7 and disconnecting the motor from the movable member of the tripping mechanism. The movable member of the tripping mechanism, therefore, flies" back and cannot again be moved until the parts are reset and the motor is thrown into operative position, which is accomplished by permitting the escape of the fluid under pressure from the casing and allowing the piston to move upwardly again until the catch 5 engages the pin 6. This resetting of the mechanism is accomplished by the movement of either hand of theoperator in again placing the material in the punch to be operated on. The forward movement of the hands, as before described, opens the valve 14 to permit the escape of the fluid under pressure from the casing of the fluid pressure motor, thereby permitting the piston to rise. In order now to again cause the press to operate, it will be noted that both hands of the operator must be again moved out of the danger zone.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is- 1. In a device of the character described,

. the-combination with a movable member for tripping the clutch of a press, of a fluid pressure motor for operating said movable member and means movable with the hands or the operator, said means being so arranged that both hands of the operator must be out of the danger zone of the mechanism of'the press before said means will cause the motor to operate.

2. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of a fluld pressure motor for operating said movable memthe combination with a movable member for tripping the clutch of a press, of a fluid pressure motor, means forrende'ring said motor inoperative with respect to said movable member after it has moved the member to trip the press, controlling means for said motor movable with the hands of the operator, said controlling means being so arranged that when either of the hands is moved toward the mechanism of the press,

the motor will be restored to operative position, but cannot be caused to operate until both hands of the operator are moved out of the danger zone of the mechamsm of the press.

4. In a device of the character described, the combination with a movable member for controlling the clutch of a press, of a fluid pressure motor for operating said movable member, a pair of valves for controlling the admission of fluid under pressure to said motor, and a pair of members movable with the hands of the operator, said valves being so arranged that they will not admit fluid under pressure to the motor until both of 5. In a device of the character described,

her, and a pair of movable members movthe combination with ainovable member for tripping the clutch of a press, of a fluid pressure motor for operating said movable member, a pair of valves arranged in series for controlling the admission of fluid under pressure to said motor, and a pair -of mov able membere for operating said valves movable with the hands of the operator, said valves being so arranged that both hands of the operator must be out of the danger zone of the mechanism of the press before fluid under pressure will be admitted to said motor.

6. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of a fluid pressure motor for operating said movable member, means for rendering said motor inoperative with respect to said movable member after the clutch has been tripped, a

pair of valves for controlling said fluid pressure motor to cause the same to operate and to restore the same to operative position, said valves being arranged in multiple for restoring the motor to operative position and in series for causing the motor to operate, and a pair of movable members for controlling said valves movable with the hands of the operator and so arranged that both hands of the'operator must be out of the danger zone of the mechanism of the press before the motor will be caused to operate.

7. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of a fluid pressure motor for operating said movable member, means for rendering said pressure motor inoperative with respect to said movable member after the clutch has once been tripped, means for controlling said pressure motor movable with the hands of the operator, said means being so arranged that when either hand of the operator is moved toward the mechanism of the press the m0- tor will be restored to operative relation with respect to said movable member, but cannot be operated until both hands of the operator are moved out of the danger zone of the mechanism of the press.

8. In a device of the character described, the combination with a movable member for controlling the clutch of a press, of a fluid pressure motor for operating said movable member, means for rendering said motor inoperative with respect to said movable member after the clutch has once been tripped, a pair of valves for restoring said motor to operative relation and for causing said'motor to operate, a pair of movable members movable with the hands of the operator for controlling said valves, said valves being so arranged that when either hand of the operator is moved toward the mechanism of the press, the valve controlled by said hand will restore the motor to operative position, but both hands of the operator must be out of the danger zone of the mechanism of the press before the valves will cause said motor to operate.

9. In a device of the character described, the combination with a movable member for tripping the clutch ofa press, of a fluid pressure motor for operating said movable member, and manual means for controlling the operation of the motor, including means whereby both hands of the operator must be out of the danger zone of the mechanism of the press before said means will cause the motor to operate.

' to said motor from a source of fluid under pressure, valve mechanism in said connection, a machine having a tool which moves in a definite path, means whereby the movement of said motor causes said tool to move, and manual means foroperating said valve mechanism to open communication between said source and motor including means whereby both hands of the operator must be out of the path of the tool, before said com-' munication is opened.

12. A safety device for a machine tool comprising a fluid motor for controlling its operation, a conduit leading to said motor from a source of fluid under pressure, and a plurality of valve mechanisms interposed in series in said conduit, each valve mechanism comprising means which in one position'afford communication between the parts of the conduit on either side of it, and in another position place that part of the conduit adjacent it and nearest the motor in communication with the atmosphere.

13. A machine having a part movable in a definite path, in combination with automatic fluid pressure means whereby the movement of the hand of the operator to a position adjacent the path of said part will prevent movement of said part and whereby movement of the hand of the operator to a position away from the path of said part will causemovement of said part.

14. A machine having a part movable in a definite path in combination with automatic fluid pressure means whereby the movement of either hand of the operator to a position adjacent the path of said part will prevent movement of said part, and whereby movement of both hands of the operator to a position away from the path of said part will cause movement of said part.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

REUBEN B. BENJAMIN. Witnesses:

W. PERRY HALSEY, ANNE SOLOMON. 

